Multiple virulence genes and other MRNA regulatory targets are differentially expressed in two Helicobacter pylori strains overexpressing small RNAs

<p>Helicobacter pylori is a bacterial pathogen infecting the stomachs of half of humanity and the first bacterium listed as a carcinogen. Strains possessing the cytotoxin-associated gene pathogenicity island (cagPAI) are especially likely to cause symptomatic disease and cancer through the action of the cagPAI Type IV secretion system and its associated cytotoxin, CagA. Although the genetic regulation necessary for these and other virulence traits is complicated by a relative lack of regulatory proteins in H. pylori, its wealth of small RNAs (sRNAs) may also regulate mRNAs, including in the cagPAI. The nascent body of work in H. pylori sRNAs supports consequential roles for posttranscriptional regulation by sRNAs, and the clinical relevance of the cagPAI further suggests these for understanding riboregulation in a pathogen. Thus, I elected to study two sRNAs occurring antisense to cagPAI genes (HPnc2540 and cagY; HPnc2620 and cagS). By modifying strains of H. pylori to overexpress one of these two sRNAs with the strong endogenous CagA promoter (PcagA), I isolated high-quality total RNA from these strains and 26695 (wildtype). Next-generation RNA-sequencing and differential gene expression analyses in these strains’ total mRNA transcriptome allowed me to observe regulatory effects of the overexpressed sRNAs amplified to a measurable degree. Analyses showed 13 total mRNAs regulated by sRNA2540 and/or sRNA2620. Ten of these are regulated by both, including three cagPAI genes and three non-cagPAI virulence genes; two other cagPAI genes are regulated by sRNA2620 alone. Implications of these results include a contributory role of regulation by cagPAI sRNAs to virulence-related traits and phenotypes. This study supports combining overexpression and RNA-sequencing as an effective methodology for exploring regulation by small RNAs in this prevalent and carcinogenic bacterial pathogen and suggests intriguing further explorations of riboregulation by H. pylori sRNAs.</p>

Name thesis:degree_name

Master of Science (MS) in Biology

Level thesis:degree_level

Thesis: EWU Only

Discipline thesis:degree_discipline

Biology

Year

2024

Author dc:creator

• McPeck, Roxanne N.

• Immunopathology
• Pathogenic Microbiology

Statement dc:rights

• Access perpetually restricted to EWU users with an active EWU NetID

Repository record dc:identifier

https://dc.ewu.edu/theses/942

OAI identifier oai:identifier

oai:dc.ewu.edu:theses-1938